Traditionally, labels were attached by adhesive means to portions of the outer surface of containers to identify the enclosed products. This concept was particularly valid in the case of glass or plastic containers that could be more easily labeled than printed. More recently, labels have been used as surface ornamentation for most or all of the surface of the container, in addition to providing the necessary identification and information. Such full surface labels are often provided as a tube that is placed over the container and subsequently caused to shrink to snugly fit the container's contour. The tube is either made by tubular extrusion or by welding opposed longitudinal edges of an elongate sheet. The same advantage as noted above is obtained by printing the tubular label, rather than printing directly on the container, to decorate the container and identify the contents. Numerous products are being marketed today in containers with tubular labels.
Some containers are sealed by the application of a tubular band that covers all or a portion of the container neck and closure. Bands are generally shorter than labels. Bands serve as a tamper-evident indicator, thus improving product safety.
Tubular labels or bands can be supplied in cut lengths and fed from a magazine to the application machine, or supplied in continuous length on a roll, in which case the tubular supply is cut into pieces of a desired length in the applying machine. Tubular labels and bands are typically formed of polyvinyl chloride (PVC) or polyethylene (PE) resin. The process of applying a tubular label or band from a supply roll to a container involves the steps of drawing a length of tubular material from the supply, cutting the length of tubular material from the supply, reconfiguring the tubular material from a flat to an open cross section and placing the open cross section tubular material over the container in the selected position. The material may be substantially elastic and stretched to fit over the container, allowing the material to recover and to grip the container. Alternately, the material may be heat shrinkable, in which case the tube is placed loosely over the container and subsequently shrunk. The present invention is mainly directed to the application of labels and bands made of heat shrinkable material.
A machine for applying tubular labels to containers is disclosed in U.S. Pat. Nos. 5,305,578, No. 5,495,704 and No. 5,711,135 to Menayan. The Menayan apparatus utilizes a series of movably mounted suction cups for gripping successive cut bands. The suction cups are moved laterally to open the band from its flattened supply condition to an open application condition. A plunger is mounted angularly above the open band and activated to drive the leading band edge onto a leading edge of a container passing therebelow at the same time as an air blast is used to maintain the band in an open condition.
A further machine for performing such a handling process for a tubular band is the subject of U.S. Pat. No. 4,914,893 to Strub et al., entitled Large Size Container Banding Apparatus. The Strub et al. invention draws a length of tubular banding material from a supply roll of flat tube and expands the banding material to a substantially round cross section by pulling the banding material over an inserted wedge device which has rollers for smoothing edge creases that were formed in the previously flat tube. As the tubular band is cut to a desired length, a suction cup suspension means attaches to the band to maintain control during application of the band to the container closure. The band is subsequently heat shrunk to snugly surround the container closure and neck.
The present invention disclosed and claimed below provides a novel improvement over all known prior patents for the high speed expansion and mounting of short bands or full cover tubular labels to containers.
The present invention to be described below enables a large variety of band sizes to be applied to containers at a rapid rate and with relatively few moving machine parts. In this way, the present invention affords a simple, efficient band or label application apparatus and method.